Motivation

Past experience with tokamaks such as TFTR and JET has shown that significant amounts of dust are formed in these machines. Dust can arise from a variety of plasma-facing components, including C, W and Be as well as other materials used in some fusion devices such as Mo, B and Ti. Dust may also come from other components in the machine, such as RF antennas.

Accumulation of dust can become a significant safety hazard due to flammability, toxicity, potential respiratory problems and radiation concerns with tritium. Furthermore, a significant uptake of hydrogen isotopes occurs in dust, making the transport behaviour of this material a significant factor in tritium inventory studies of next generation machines such as ITER and DEMO. Dust contaminated with tritium can become electrically charged from radioactivity, leading to the interaction of the dust with the plasma and electric fields. These issues are not of high importance for operational machines, but will become significant for ITER and later machines due to the significant increased size of the plant.

Therefore, there is a need for information on properties of dust, such as particle size distribution (physical and aerodynamic mass median diameter), composition (elemental and chemical) and their origins in fusion machines. There is currently a lack of data on these fundamental physical and chemical properties; the primary goal of this CRP[1] is to address these data needs.

CRP(2008-2012) Research Activities

Presentations of the following topics can be found at IAEA webpage[1].